Taking stock of Koji Uehara’s historic year

The inning hardly seemed remarkable. Koji Uehara punched in for a routing pre-layoff tuneup, tossing a scoreless eighth inning in which he allowed a double while striking out a batter. As has become the norm, he threw 12 pitches, 11 for strikes.

But that contribution in a 7-6 contest represented the final note of an historic achievement. With the outing, Uehara concluded the year with a 1.09 ERA (best in the majors of any pitcher with 50 or more innings) and a mind-blowing average of 0.57 walks plus hits per nine innings — the lowest WHIP in baseball history by a pitcher who logged at least 50 innings, surpassing by a considerable margin the 0.61 standard set by Dennis Eckersley in 1989.

What he accomplished over a full year represented one of the greatest years in the history of the ninth-inning closer. How to describe what he did, and the dominance he exhibited?

“When you’re surprised that he gives up a baserunner, that means he’s having a pretty good year,” said teammate Craig Breslow. “Maybe my metrics are a little bit subjective, but when you can’t remember the last time a guy’s been on base, he’s having a good year. He’s been absolutely dominant, especially considering that coming into the season he was probably the third, fourth, fifth option to close.

“We’re celebrating the retirement of the greatest closer to play this game,” Breslow continued, alluding to Mariano Rivera, whose lowest ERA was 1.38 (in 2005) and whose lowest WHIP was 0.66 (in 2008), “and the run that Koji’s been on, nobody can touch. ”

A few other markers of Uehara’s absurdly, historically great season:

— He struck out 101 batters and walked nine. In the process, Uehara became the first person ever with more than 100 punchouts and fewer than 10 walks. It’s worth noting that two of his nine walks were intentional.

— He threw strikes on 74 percent of his pitches, the highest recorded percentage in the annals of the indispensable Baseball-Reference.com of any pitcher who worked at least 50 innings in a year. (B-R’s records on strike percentage date back just to 2000.)

— Uehara did not walk a batter in his last 22 appearances, dating to Aug. 4.

— In the final three months of the year, he allowed one earned run in 37 games spanning 40 1/3 innings, good for a 0.22 ERA, with 52 strikeouts and two walks during the stretch.

— In save situations, he had a 0.72 ERA with 36 strikeouts and one walk in 25 innings, with a 0.72 ERA. Of his 21 saves, 19 have been perfect appearances. He led all big league relievers with 44 perfect games (no baserunners), and led American League relievers with 65 scoreless appearances.

— He has struck out 30.2 percent of all batters he’s faced in his career — the ninth highest strikeout rate of all times with careers of at least 200 innings.

In the process, Uehara emerged as a pivotal figure in the regular season, and a strong case can be made that, given the struggles of the Sox’ middle relievers, he is the most important member of the roster in the postseason — a status that, in turn, could alter the prior obscurity in which Uehara often has found himself, much to his chagrin.